3-Hydroxypropionate (“3-HP”, CAS No. 503-66-2) is a carboxylic acid that is a highly attractive chemical feedstock for the production of many large market commodity chemicals currently produced from petroleum derivatives. For example, commodity products that can be readily produced using 3-HP include acrylic acid (AA), 1,3-propanediol, methyl-acrylate, and acrylamide. The sum value of these commodity chemicals is currently estimated to exceed several billion dollars annually in the U.S. In addition, manufacture of the same commodities via the clean, cost-effective production of 3-HP from biomass will substitute renewable feedstocks for non-renewable resources.
Production of 3-HP is only one important part of the 3-HP procurement process. Another critical step in the process of 3-HP procurement is the purification of 3-HP, whether from a medium used for biological production (e.g., fermentation broth) or a medium used for chemical synthesis. Of particular interest is providing a process for the purification of 3-HP regardless of the form of the 3-HP, for example purification of 3-HP from a medium (such as a fermentation medium) where it exists in a salt form such as a sodium or calcium salt.
Purification of 3-HP is particularly challenging. 3-HP is very hydrophilic and, as a result, is very difficult to separate from water. Traditional distillation techniques to purify 3-HP are ineffective because 3-HP decomposes (e.g., dehydrates to acrylic acid) at elevated temperatures before it vaporizes.
A variety of other purification methods have been explored for the purification of carboxylic acids, primarily lactic acid. These purification methods, however, often employ organic solvents, solid adsorbents, reactive amines, and/or energy-intensive processes.
There remains a need for methods of purifying 3-HP that minimize the use of organic solvents, highly acidic solutions, and other chemicals.